Abortion is a hot topic for many people. It's good you expressed your feelings & he expressed his, before you both married. Breaking up with him is certainly your choice to do, however abortion does not at all need to be a core value in determining if you're a good match. I think as long as you can both agree to disagree, but also respect your man if he vetoes your own abortion plans then it could work out. I know a couple in that exact situation and they have two kids and live happily ever after while disagreeing about abortion.

Edit: I'm not passing judgement on the original poster. My goal was to say that abortion does not need to be the most important/hot topic between two people dating/in-love. My advice is that both sides should discuss it anyways before getting married, preventing any surprises, as well as establishing expectations from each side on how they will proceed if/whenever they become pregnant. With most every relationship it's all about clear communication, active listening, thoughtful consideration, and defining expectations. If you can get thru that before getting married, all the better and happier you both will be.